Polymers containing maleimide group(s) either at the chain end(s) or as pendant groups are of great interest in view of the demonstrated capability of maleimide group to participate in highly efficient chemical reactions such as addition of thiol over the vinyl double bond and Diels-Alder reaction with suitable dienes such as furans and anthryl. Polymers possessing maleimide group(s) at chain end(s) are accessible by chain polymerization of addition monomers with appropriate (protected) maleimide containing initiator or by chemical modification of functionally-terminated polymers with maleimide containing reagents. Polymers bearing pendant maleimide groups have been synthesized by chain polymerization of addition monomers or by step growth polymerization of condensation monomers containing maleimide groups. Chemical modification approach has also been employed to synthesize polymers with pendant maleimide groups.
Bisphenols are a versatile class of monomers and are useful as building blocks for synthesis of a range of polymers such as polycarbonates, polyesters, polyether sulfones, polyether ketones, epoxies, etc. Furthermore, bisphenols possessing pendant functional groups provide an access to above mentioned polymers containing the respective pendant functional groups which could be subsequently exploited as reactive sites for chemical modifications. Bisphenols containing pendant functional groups such as hydroxyl, halogen, carboxyl, primary amine, tertiary amine, azido, furyl, alkene, etc are known in the literature. However, examples of bisphenols containing pendant maleimide group are limited. Bisphenols containing pendant maleimide groups find applications in the preparation of high performance polymers such as polycarbonates, polyesters, polyether sulfones, polyetherketones, epoxies, etc. The pendant maleimide groups provide interesting opportunities for chemical modifications and crosslinking reactions.
U.S. Pat. No. 7,135,577 B2 and US 2005/0222334 A1 discloses a method for producing and purifying 2-hydrocarbyl-3,3bis(4-hydroxyaryl)phthalimidine monomers, and polycarbonates as well as other polymers derived utilizing the monomers. The method comprises forming a reaction mixture comprising at least one substituted or unsubstituted phenolphthalein, at least one substituted or unsubstituted primary hydrocarbyl amine, and an acid catalyst; and heating the reaction mixture to a temperature of less than 180° C. to remove a distillate comprising water and form a crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product; where the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine has a formula:
where R1 is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R2 is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen.
CN103373950A discloses a maleimide group-containing bisphenol monomer, it's synthetic method and applications. The maleimide containing bisphenol monomers, of the following structure:
Wherein, the maleimide groups are directly attached to aromatic ring have been disclosed.
U.S. Pat. No. 4,514,334 relates a polyphenolic compound of the formula, wherein Ar is a mono, -di- or trinuclear aromatic C6-14 hydrocarbon radical; R is hydrogen or a C1-C5 alkyl radical; each X substituent is independently selected from H, Cl, Br, C1-C5 alkyl and phenyl; and n is either 2, 3 or 4.
U.S. Pat. No. 7,425,603 B2, US 2007/0123682 A1 and US20070123713 A relates to a process of forming a polycyclic dihydroxy compound as shown below.
wherein R1, R2 and R3 are independently at each occurrence selected from the group consisting of a cyano functionality, a halogen, an aliphatic functionality having 1 to 10 carbons, a cycloaliphatic functionality having 3 to 10 carbons, and an aromatic functionality having 6 to 10 carbons; and wherein each occurrence of “n”, “m”, and “p” independently has a value of 0, 1, 2, 3, or 4. Also described are polycyclic dihydroxy compounds of Formula (I) in which the phthalimide group is meta to the triaryl-substituted carbon.
Article titled, “Maleimide-containing polyamides” by Camelia Hulubei in Materiale Plastice 45Nr. 3, 228, 2008 reports functional polyamides with pendant hydroxyl groups prepared by the direct polycondensation of 5,5′-methylene-bissalicylic acid, with various diamines (p-phenylenediamine, 4,4′-oxydianiline and 4,4′-methylenedianiline) in N-methyl-2-pyrrolidone, using triphenyl phosphite and pyridine as condensing agents. The resulting polymers were chemically modified with 4-maleimidobenzoyl chloride, resulting in polyamides with maleimide pendant groups. The polymers were soluble in dipolar aprotic solvents such as dimethylsulfoxide, dimethylformamide, and were thermally stable up to 314° C. The chemically modified polyamides exhibited better solubility and thermal stability than their unmodified counterparts.
Article titled, “Synthesis and post-polymerization modification of maleimide-containing polymers by ‘thiol-ene’ click and Diels-Alder chemistries” by Daniel J. Hall et. al in Polym. Int., Volume 60, Issue 8, pages 1149-1157, August 2011 reviews the versatility and utility of the maleimide group in the efficient functionalization of polymers by both ‘thiol-ene’ Michael addition and Diels-Alder cycloaddition chemistries. US 2005/0228137 A1 relates to a polymer blend consisting essentially of at least one thermoplastic polymer, and a polymer comprising structural units derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
Article titled, “Phenolphthalein-based cardo poly(arylene ether sulfone): Preparation and application to separation membranes.” Gao, N. and Zhang, S. in J. Appl. Polym. Sci., 128: 1-12. doi:10.1002/app.38810 reviews the synthesis of phenolphthalein-based cardo poly(arylene ether sulfone)s, including synthesis of cardo bisphenols and their polymers, and their application to gas separation membranes.
U.S. Pat. No. 4,134,936 discloses novel copolycarbonates exhibiting generally improved impact resistance, clarity and flame resistance are prepared by blending a polycarbonate of a trityldiol such as phenolphthalein and a polycarbonate of another diol such as bisphenol-A under conditions of temperature and/or shear sufficient to cause reaction of the polycarbonates.
However, bisphenols possessing pendant maleimide groups which are connected via alkylene spacer are not reported in the prior art. Therefore, it is the need to develop bisphenols starting from commercially available and inexpensive chemicals and possessing pendant maleimide group which is connected via alkylene spacer.